From df22095d4458a7e2c450446928c2c2becfb40339 Mon Sep 17 00:00:00 2001 From: Corbin McElhanney Date: Wed, 9 Aug 2017 10:30:28 -0400 Subject: [PATCH 0964/4131] drm/amd/display: Add comment explaining context free This comment explains a previous change that adds some complexity to the context free in dc: commit 9ad58779a895 ("drm/amd/display: Fix accessing freed memory") Signed-off-by: Corbin McElhanney Reviewed-by: Tony Cheng Acked-by: Harry Wentland --- drivers/gpu/drm/amd/display/dc/core/dc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c index 6b29ea5..04547fb 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c @@ -1740,6 +1740,15 @@ void dc_update_planes_and_stream(struct dc *dc, } if (core_dc->current_context != context) { + + /* Since memory free requires elevated IRQL, an interrupt + * request is generated by mem free. If this happens + * between freeing and reassigning the context, our vsync + * interrupt will call into dc and cause a memory + * corruption BSOD. Hence, we first reassign the context, + * then free the old context. + */ + struct validate_context *old = core_dc->current_context; core_dc->current_context = context; -- 2.7.4